1. Field of the Invention
The invention relates generally to a structure that performs the dual function of reaction catalyst and mass transfer surface for distillation. More particularly, the invention relates to a fixed distillation structure which contains a solid particulate catalyst.
2. Related Art
The concurrent reaction and separation of products from reactants has been practiced for some time, and the advantages have been recognized. Examples of the use of concurrent reaction and distillation are disclosed in U.S. Pat. Nos.: (etherification) 4,232,177; 4,307,254; 4,336,407; 4,504,687; 4,918,243; and 4,978,807; (dimerization) 4,242,530; (hydration) 4,982,022; (dissociation) 4,447,668; and (aromatic alkylation) 4,950,834 and 5,019,669.
Several different catalytic distillation structures have been proposed. See for example U.S. Pat. Nos. 4,302,356 and 4,443,559 in which a particulate catalyst is contained within the pockets on a cloth belt wound with demister wire to form a catalytic distillation structure and U.S. Pat. No. 4,731,229 which discloses a packing with corrugated elements and tape form catalyst member. More recently high efficiency packing has been modified to contain catalyst as is disclosed in U.S. Pat. No. 5,073,236. In the latter each of the structures, comprising two parallel gas permeable plates having the catalyst between them, are vertically placed within a column directly adjacent another pair of the plates containing the catalyst. The close packing of plates containing the catalyst when placed into the column may present too dense a catalyst bed in some instances and thus increase the residence time beyond that necessary for a given reaction. It is an advantage of the present invention that greater mobility of fluids within the columns can be obtained in some of the embodiments. It is a further advantage that the catalytic distillation structure offers better distillation characteristics than many of those of the prior. It is a feature of the present invention that less catalytic material may be employed with the present structures.